Planar electrode sensors can be used e.g. in floor constructions to electrically monitor the movements and locations of a person, as is described e.g. in publication WO2005/020171A1. This type of sensor can be used e.g. to monitor elderly people in a room, more particularly their movements and their vital functions. Publication WO 2006/0023245 presents one sensor construction for detecting an electrical field, wherein the sensor is in web form and comprises sequential electrically conductive areas. The electrically conductive areas are typically metallic, and they can be formed on a substrate, e.g. as printed layers, laminated layers, etched layers, or films. The metal is typically aluminum or copper, as is disclosed in publication WO2008068387A1. The sensor web according to the publication in question can be manufactured by laminating a metal foil to a release web, after which the electrically conductive areas and the foil-type connection leads in connection with them are stamped out of the metal foil. After that a protective layer is laminated onto the electrically conductive foil-type areas and connection leads, the release web is removed and a backing film is laminated to replace the release film. The manufacturing method in question can be applied also to the types of sensor webs that comprise two or more superimposed layers. In that case the first layer can comprise conductive areas and their leads, and the second layer e.g. RF loops and their leads. The sensor web comprises an output connection for connecting it with a connection cable to the control electronics for supplying measuring voltages and control signals via the connection in question.
In addition, foil-type floor heating systems are known, wherein metallic heating foils, which are disposed under the floor covering, are used for the heating of the floor. The foil is connected with connection cables to a control and current supply apparatus, and the foil is heated by means of electric current. Heating foils generally operate with a mains voltage of 230 V and their output power is typically in the range 50-200 W. One electrical heating foil is disclosed in U.S. Pat. No. 3,721,800, in which an aluminum foil having a thickness of approx. 0.05 mm is used. The foil is insulated on both its surfaces, and it forms a pattern comprising parallel narrow branches, which are connected to each other at their ends with bridges.
A particular drawback in these prior-art solutions is that if it is desired to use floor heating in the rooms in which it is desired to simultaneously monitor the vital functions and movements of the resident of the room by means of a floor sensor, it is necessary to use separate sensor foil and heating foil systems, which is complex and expensive.